RM 125 - a or B

[80-85 husky]

will a TS 185 donk drop into one of these frames?? I know the ts 125 and rm s have swappable engines. maybe  a neat little project to get a TS with a little better suspension and steering.

[pokey]

 not sure but a 185 will fit into a tm125 frame easily . just move one rear engine mount.

 Was a yellow and orange Rm185 on fleabay last year. it looked very nice but useless for racing..

 Try just putting a set of decent forks on a 185 frame.. you could be suprised

[bigk]

What are you trying to achieve? I've built an "RM175" using a 125 B chassis & PE175 engine with mods, a stock RM125 is a way better MX bike and I've had a KX125 A5 with 175 cylinder, once again a stock KX125 is way better MX bike. Both are called cheat bikes but it's hardly cheating when they perform at a lower level. Might be an ok thing for a vinduro.
K

[John Orchard]

I guess it's only cheating if you run in the 125 class, perfectly legal, and fun in the 250 class, I would think.

[80-85 husky]

years ago I had a registered rm 125 S by wacking a ts 125 motor in (exact same cases as the "S") it wasn't overly powerful. and yes for Vinduro would be the most use for it. the 185 having a little more low  end than the rm's of the time and the ts 125. just thinking it would be an interesting project to put together as long as the ts 185 motor would bolt straight in. I suspect it doesn't in the a and b's as they were different engines to the S.

[oldmxracer]

FWIW, I built/raced an N using an 82 PE motor in AHRMA 50+ Int (mid pack guy). Turned out great. Minor grinding on the cases and swapped the stinger from the 125 to the 175 pipe to clear the airbox. Some port work and used the 125 ignition. I was surprised how well it all worked. On some tracks it might have actually been an advantage at my ability level, but no holeshots!

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[LWC82PE]

I think you could do it if you had a pre-reed/ non-centre port 185 motor. Would be a interesting bike, but like pokey said, maybe look into changing front and rear ends on a stock 185 instead?

[80-85 husky]

I thought about the ts with bigger suspenders but it has trailbike ride traits, geometry etc and I struggle with that.

the little RM / ts I did steered real nice and rode well. lots better that the stock TS.

I would use an early TS motor and build a nice down pipe for it after a few internal mods to strengthen the power a bit.

in hind site, an early PE 175 is probably the simplest way to go being an uprated 125 engine in an rm style frame....

its not for viper so age and components don't matter its just a project I have had in my mind and was wondering if anyone had tried it before. the i75 in the rm frame is probably a good indication that its not impossible.

[TT5 Matt]

the ts185 motors are too long for the rm125A on frames and lack case reed valving/6 speed box that the pe175 has.a pe175 barrel will take a 185 piston though once your out of 175 oversize pistons, hell you might even be able to mix and match the gear ratios for a bike able to do most roles well

[80-85 husky]

I will just get a PE 175 and put a ts 185 tank on it solved...